<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>null,undefined全等于</title>
</head>
<body>
<script>
    console.log(null===undefined);//false;
    console.log(null==undefined);//true;
    console.log(Boolean(-3));//true;
    console.log(0.1+0.2==0.3);//false;
    console.log(0.15+0.25==0.4);//true;
    var a=123;
    console.log(a.toString());//"123"
</script>
</body>
</html>